基于切削热-力耦合效应的表面强化技术及其工艺试验研究

Experimental Research on Surface Reinforcement Mechanism Introduced by Coupling Effect of Cutting Forces and Heat

经过对超高强度钢工件高速切削加工表面质量的系统研究,发现在某种特定的切削条件下,工件表面质量将会发生显著改变。该变化不仅表现为表面特征的大幅改善,如表面粗糙度可以控制在0.4μm以下,无宏观裂纹发生等,还表现为表层及次表层显微硬度的明显提高、最大残余压应力深度的大幅增加(达到0.35 mm)以及表面耐磨性能的显著增强等。研究结果表明,合理的切削工艺将极有可能成为一种能够在获得工件结构形状与精度指标的同时,对加工表面表层、次表层的组织特性与工件使用性能产生积极影响的表面强化手段。

HSC （ High Speed Cutting） of ultra-high strength steel was conducted in a design of statistic analysis to investigate the coupling effect of mechanical load and thermal load on the surface quality of workpieces. The experimentation demonstrated that the HSC machined surfaces could exhibit significant changes in the surface quality, such as low surface roughness （ Ra 〈 0.4μm） , free of microcracks, and reasonable residual stress profiles. The micro-hardness on the surface and sub-surface layer was remarkably increased, the maximum compressive residual stress value was dramatic increased and the compressive residual stress could notably expand to 0. 35 mm beneath the machined surfaces. This study indicated that the properly controlled HSC process could be used as a high efficient surface strengthening method which could significantly increase the workpiece＇ s microstructure properties and service performances with high material remove rate.